<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>

	<style>
		* {
			padding: 0;
			margin: 0;
		}

		.con {
			width: 40rem;
			height: 10.6666666667rem;
			background-color: #00557F;
		}
	</style>
	<body>
		<div class="con"></div>
	</body>
	<script>
		function resize() {
			if (document.documentElement.clientWidth >= 600) {
				document.documentElement.style.fontSize = '30px'
				return
			}
			document.documentElement.style.fontSize = document.documentElement.clientWidth / 20 + 'px'
		}
		resize()
		window.onresize = resize
	</script>
</html>
